Leptoproduction of J / psi
Thomas Mehen · arXiv (Cornell University) · 1998
I review the status of the extraction of NRQCD color-octet $J/\\psi$ production matrix elements. Large theoretical uncertainties in current extractions from hadroproduction and photoproduction are emphasized. Leptoproduction of $J/\\psi$ is calculated within the NRQCD factorization formalism. Color-octet contributions dominate the cross section, allowing for a reliable extraction of $$ and $$. A comparison with preliminary data from the H1 collaboration shows that leading order color-octet mechanisms agree with the measured total cross section for $Q^2 > 4m_c^2$, while the color-singlet model underpredicts the cross section by a factor of 5.